Valve lifter

ABSTRACT

A valve lifter of a valve train of an engine is provided. The valve lifter includes a first end adapted to engage with a cam of the engine. The valve lifter also includes a second end distal to the first end. The second end is adapted to engage with a pushrod of the valve train. The valve lifter further includes a flat surface provided on an outer surface of the valve lifter. The flat surface is adapted to engage with a protrusion provided in a cylinder head of the engine. The fiat surface of the valve lifter is arranged and adapted to mate with the protrusion of the cylinder head.

TECHNICAL FIELD

The present disclosure relates to a valve lifter. More particularly, the present disclosure relates to the valve lifter of a valve train of an engine.

BACKGROUND

Generally, a valve train of an engine employs a valve lifter, a pushrod, and/or a hydraulic lash adjuster to transmit motion from a rotary cam to a rocker arm of the valve train. During operation of the engine, the valve lifter may translate along a longitudinal axis thereof to convert a rotary motion of the cam to an oscillatory motion of the rocker arm. Additionally, in some circumstances, the valve lifter may also rotate along the longitudinal axis during the translatory motion thereof.

Due to the rotation of the valve lifter, an alignment between components of the valve train may be altered. For example, a roller of the valve lifter may be required to be correctly aligned with respect to the cam for smooth engagement therebetween. In case of rotation of the valve lifter, the roller may be misaligned with respect to the cam leading to incorrect engagement between the roller and the cam. The incorrect alignment/engagement between the roller and the cam may cause sliding movement between the roller and the cam in turn leading to increased friction. Also, due to rotation of the valve lifter, an outer surface of the valve lifter may rub against a wall of the cylinder head.

Additionally, rotation of the valve lifter may also cause increased friction between the valve lifter and the pushrod. This in turn may further lead to alteration in clearances between mating parts of the valve lifter, the cam, the pushrod and/or the wall of the cylinder head. Change in the clearances may in turn lead to increased engine noise, increased service intervals, increased machine downtime, increased maintenance, and so on.

U.S. Pat. No. 6,732,692 describes a cylinder head gasket for use in an internal combustion engine. The gasket includes a projection arranged to engage a tappet in the engine in which the gasket is installed to prevent rotation of the tappet. The projection includes a spring biased end section arranged to engage a flat surface on the tappet.

SUMMARY OF THE DISCLOSURE

In an aspect of the present disclosure, a valve lifter of a valve train of an engine is provided. The valve lifter includes a first end adapted to engage with a cam of the engine. The valve lifter also includes a second end distal to the first end. The second end is adapted to engage with a pushrod of the valve train. The valve lifter further includes a flat surface provided on an outer surface of the valve lifter. The flat surface is adapted to engage with a protrusion provided in a cylinder head of the engine. The flat surface of the valve lifter is arranged and adapted to mate with the protrusion of the cylinder head.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary engine system, according to one embodiment of the present disclosure;

FIG. 2 is a side view of an exemplary valve train of the engine system of FIG. 1, according to one embodiment of the present disclosure;

FIG. 3 is a perspective view of a valve lifter of the valve train of FIG. 2, according to one embodiment of the present disclosure; and

FIG. 4 is a partial perspective cross sectional view of a cylinder head of the engine system of FIG. 1, according to one embodiment of the present disclosure.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts, Referring to FIG. 1, an exemplary engine system 10 is illustrated. The engine system 10 includes an internal combustion engine powered by any fuel known in the art such as gasoline, diesel, natural gas, and so on, or a combination thereof. The engine system 10 may be used for applications including, but not limited to, power generation, transportation, construction, agriculture, forestry, aviation, marine, material handling, and waste management.

The engine system 10 includes an engine block 12. The engine block 12 includes one or more cylinders (not shown) provided therein. The cylinders may be arranged in any configuration such as inline, radial, “V”, and so on. The engine system 10 also includes a cylinder head 14 mounted on the engine block 12. The cylinder head 14 houses one or more components and/or systems (not shown) of the engine system 10 such as a valve train, an intake manifold, an exhaust manifold, sensors, and so on. Additionally, the engine system 10 may include various other components and/or systems (not shown) such as a crankcase, a fuel system, an air system, a cooling system, a turbocharger, an exhaust gas recirculation system, an exhaust aftertreatment system, other peripheries, and so on.

Referring to FIG. 2, the engine system 10 includes a valve train 16. The valve train 16 includes a valve 18. The valve 18 is provided in association with an inlet port (not shown) or an outlet port (not shown) of the cylinder head 14. The valve 18 selectively opens or closes the inlet port or the outlet port during operation of the engine system 10. The valve train 16 includes a valve spring 19 coupled to the valve 18. The valve spring 19 biases the valve 18 in an open position or a closed position based on application requirements.

The valve train 16 includes a rocker arm 20. The rocker arm 20 has a first end 22 and a second end 24. The first end 22 of the rocker arm 20 is coupled to the valve 18 through a valve bridge 26. In some embodiments, the first end 22 of the rocker arm 20 may be directly coupled to the valve 18. In such a situation, the valve bridge 26 may be omitted. The valve train 16 includes a rocker stand 28 provided on the cylinder head 14. The rocker stand 28 is pivotally coupled to the rocker arm 20. The rocker stand 28 supports the rocker arm 20 and allows an oscillatory motion of the rocker arm 20.

The valve train 16 includes an adjustment screw 30. The adjustment screw 30 is coupled to the second end 24 of the rocker arm 20. The adjustment screw 30 is adapted to adjust a valve clearance based on application requirements.

The valve train 16 also includes a pushrod 32. The pushrod 32 has a first end 34 and a second end 36. The first end 34 of the pushrod 32 is coupled to the adjustment screw 30. In some embodiments, the adjustment screw 30 may be omitted. In such a situation, the first end 34 of the pushrod 32 may be coupled to the second end 24 of the rocker arm 20. The second end 36 of the pushrod 32 is coupled to a valve lifter 38.

In some embodiments, the valve train 16 may also include a Hydraulic Lash Adjuster (HLA) (not shown) coupled between the first end 34 of the pushrod 32 and the adjustment screw 30, or the second end 24 of the rocker arm 20. The HLA may be adapted to maintain a required valve clearance such as a zero valve clearance based on application requirements. The HLA may also be adapted to compensate for thermal expansion and reduce wear and tear of components of the valve train 16.

Referring to FIGS. 2 and 3, the valve lifter 38 includes an elongated and cylindrical configuration defining a longitudinal axis A-A′. The valve lifter 38 includes a first end 40 and a second end 42. The second end 42 is distal to the first end 40. The first end 40 of the valve lifter 38 includes a roller 44. The roller 44 contacts a cam (not shown) and rolls thereon. Accordingly, the roller 44 and the valve lifter 38 follow a motion of the cam. The second end 42 of the valve lifter 38 includes a recess 46. The recess 46 extends at least partially along the longitudinal axis A-A′ from the second end 42 toward the first end 40 of the valve lifter 38, The recess 46 receives the second end 36 of the pushrod 32 in an assembled position thereof.

The valve lifter 38 also includes a flat surface 48 provided on an outer surface 50 thereof. In the illustrated embodiment, the valve lifter 38 includes a single flat surface 48 provided on the outer surface 50 of the valve lifter 38. In other embodiments, the valve lifter 38 may include multiple flat surfaces 48 provided on the outer surface 50 thereof such as opposing one another, spaced apart at an angle with respect to one another, and so on.

In the illustrated embodiment, the flat surface 48 includes a slot 52 provided on the outer surface 50 of the second end 42 of the valve lifter 38. The slot 52 defines a width “W” and a length “L1” thereof. The slot 52 extends at least partially on the outer surface 50 of the valve lifter 38 along the longitudinal axis A-A′. More specifically, the slot 52 extends at least partially on the outer surface 50 of the valve lifter 38 along a length “L2” of the valve lifter 38 from the second end 42 toward the first end 40 thereof.

In other embodiments, the flat surface 48 may extend along complete length “L2” of the valve lifter 38. More specifically, the flat surface 48 may extend from the second end 42 to the first end 40 of the valve lifter 38. It should be noted that number, configuration and dimension of the flat surface 48 and/or the slot 52 described herein is merely exemplary and may vary based on application requirements. The flat surface 48 and/or the slot 52 may be formed by any known machining process such as milling, cutting, and so on.

Referring to FIG. 4, the valve lifter 38 is received through a bore 54 in the cylinder head 14 for operably coupling the first end 40 of the valve lifter 38 with the cam. Accordingly, a size of the bore 54 is larger than an outer diameter “OD” of the valve lifter 38. Based on a rotation of the cam, the valve lifter 38 translates along a longitudinal axis B-B′. In the illustrated embodiment, the valve lifter 38 translates in a vertical direction. In a horizontally oriented engine system 10, the valve lifter 38 may translate in a horizontal direction based on the rotation of the cam.

Further, the cylinder head 14 includes a protrusion 56 provided therein. More specifically, the protrusion 56 is provided on an inner surface 58 of the bore 54 and adjacent a top opening 60 of the bore 54. The protrusion 56 is provided in a manner such that the protrusion 56 is adjacent the second end 42 of the valve lifter 38. In an assembled position, the protrusion 56 mates with the flat surface 48 and/or the slot 52 and thereby limits rotation of the valve lifter 38 about the longitudinal axis B-B′ within the bore 54. Also, the protrusion 56 is provided in a manner such that the protrusion 56 may not limit the translatory motion of the valve lifter 38 along the longitudinal axis B-B′ within the bore 54. Accordingly, the length “L1” of the slot 52 may be equal to or greater than a translatory travel range of the valve lifter 38.

It should be noted that the protrusion 56, a location and a number thereof on the cylinder head 14 described herein is merely exemplary. In other embodiments, the protrusion 56 may be provided at any location in the cylinder head 14 in order to mate with the flat surface 48 and/or the slot 52 provided on the outer surface 50 of the valve lifter 38. Also, the number of protrusions 56 may vary based on the number of flat surfaces 48 and/or slots 52 provided on the valve lifter 38. The protrusion 56 may be formed on the inner surface 58 of the bore 54 by any known method such as welding, bolting, riveting, and so on. In some embodiments, the protrusion 56 may be integrally cast during manufacturing of the cylinder head 14.

INDUSTRIAL APPLICABILITY

The present disclosure relates to the valve lifter 38 and the protrusion 56 provided on the cylinder head 14. In the assembled position of the valve lifter 38 within the bore 54, the flat surface 48 and/or the slot 52 provided on the valve lifter 38 mates with the protrusion 56 provided on the cylinder head 14. As a result, during operation of the engine system 10, rotation of the valve lifter 38 about the longitudinal axis B-B′ within the bore 54 is limited by the protrusion 56.

Due to limiting of the rotation of the valve lifter 38, the valve lifter 38 may be correctly aligned within the bore 54 at all times as per application requirements. As a result, the roller 44 of the valve lifter 38 may correctly contact the cam and in turn may enable smooth operation therebetween. Also, rubbing of the valve lifter 38 against the bore 54 and/or the pushrod 32 may be reduced in turn leading to reduced friction therebetween. The flat surface 48 and/or the slot 52 and the protrusion 56 provide a simple and efficient means for limiting the rotation of the valve lifter 38 within the bore 54 with minor modification to the existing components.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of the disclosure. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof. 

What is claimed is:
 1. A valve lifter of a valve train of an engine, the valve lifter comprising: a first end adapted to engage with a cam of the engine; a second end distal to the first end, the second end adapted to engage with a pushrod of the valve train; and a flat surface provided on an outer surface of the valve lifter, the flat surface adapted to engage with a protrusion provided in a cylinder head of the engine, wherein the flat surface of the valve lifter is arranged and adapted to mate with the protrusion of the cylinder head.
 2. The valve lifter of claim 1, wherein the flat surface includes a slot extending at least partially along a length of the valve lifter.
 3. The valve lifter of claim 1, wherein the valve lifter has a cylindrical configuration. 